Our knowledge about psychiatric diagnoses and symptomatology among preschool and early grammar school-age children is very limited both generally and, specifically, with regard to the manner in which such problems present in primary care pediatric settings. We are currently conducting an NIMH-sponsored study (to be completed in 8/91) to examine the pediatrician's ability to identify behavioral/emotional problems among preschool children, ages 2-5 years. As part of this study, a group of 513 preschool children are being seen for a thorough evaluation of their emotional and intellectual functioning, and a consensus DSMIII-R diagnosis is assigned. We are proposing to conduct a five-year longitudinal study of this group of children (with the first year funded through the currently- funded grant and funding being sought for the next 4 years). Of the 513 children eligible for the longitudinal study, approximately 250 (40-45%) are expected to receive a psychiatric diagnosis. In the proposed longitudinal study, both children with and without a psychiatric diagnosis will be followed and seen annually for a reevaluation. The results of the study will allow us to examine: 1) the stability of psychiatric diagnoses and behavior/emotional problems of preschoolers followed in pediatric practices from preschool through early grammar school; 2) patterns of health care utilization prospectively, among children with and without a psychiatric diagnosis, including those either accurately or inaccurately diagnosed by their pediatricians at the time of the initial evaluation; 3) the relationship between sociodemographic and familial risk factors and a) changes in psychiatric status and symptomatology among preschoolers, and b) health care utilization among preschool-age and early grammar school-age children. An important, secondary product of the study will be the development of the software designed to conduct the random regression analyses necessary for appropriate analyses of such longitudinal data.